Cavity: Missing tooth structure. A cavity may be due to decay, erosion or abrasion. If caused by caries; also referred to as a carious lesion.

Clinical trial: Research studies of the preventative or therapeutic effectiveness and/or safety of a treatment or medicine. Usually evaluated by intra-group or inter-person comparison. If no current treatment or drug exists it may be tested against a placebo group.

Codeine: This medicine relieves pain. In the United States, you need a prescription from a doctor to buy codeine. It can have many side effects, including sleepiness, dizziness, breathing problems, and physical or mental dependence.

Cosmetic/cosmetic dentistry: Any services provided by dentists solely for the purpose of improving your appearance, not your health.

Crown: A crown is a single, artificial tooth that fits over a real tooth that has been specially shaped. It can also fit over a dental implant.

Deciduous teeth: These are the first teeth a child gets. They are also called primary teeth or baby teeth.

Deductible: The amount of dental expense for which the beneficiary is responsible before a third party will assume payment of benefits.

Dental arch: The dental arch is the way your teeth are lined up in a curved shape inside your mouth.

Dental bridge: This is an appliance that fills the space left by missing teeth with artificial ones, held in place by attaching to natural teeth or implants. It can be removable or fixed in place.

Dental erosion: Dental erosion is the thinning or wearing away of the hard coating of a tooth (the enamel).

Dentifrice: An old-fashioned word for toothpaste.

Dentures: A set of artificial teeth. They can replace all of one's teeth (complete dentures) or a section of teeth (partial dentures).

Denture adherents/adhesives/ creams/ powders: Used as a temporary way to hold dentures firmly in place. The adherent is applied to clean dentures that are then position in the mouth and held in place for a few moments.

Denture cleansers: Creams, pastes, gels and solutions that are made to clean both full dentures and removable partial dentures.

Dry mouth: Also called xerostomia; a condition that results from an inadequate flow of saliva.

First molars: These are the molars (big teeth that you chew with) that are closest to the front of your mouth.

Floss: Thick string used to remove food trapped between your teeth and remove bacteria that cannot be reached by brushing alone. It is usually made from nylon filaments or plastic monofilaments and may be treated with flavoring agents to make flossing more pleasant.

Fluoride: A mineral that helps prevent tooth decay (cavities).

Fluoride varnish: A liquid, containing fluoride, that is painted onto the teeth and hardens.

Gingivitis: Inflammation of gum tissue without loss of connective tissue.

Gum disease: A disease that may cause gums to be red, swollen and bleed easily. If it is not treated, gum disease can get worse and damage the tissues that hold your teeth in place. It is also called gingivitis or periodontal disease, depending on the severity.

Malocclusion: This term is used to describe teeth that don't line up correctly in the mouth. They may be too far apart, crooked or may not come together right when you bite down.

Molars: The large teeth in the back of your mouth. We use our molars to chew food.

Mouthrinse: An oral rinse that can be used to freshen breath, help prevent or control tooth decay, reduce plaque, prevent or reduce gingivitis, reduce the formation of tartar, or a combination of these effects. Usually available without a prescription.

Opioids: This medicine relieves pain. You need a prescription from a doctor to buy opioids. Opioids may make you sleepy or dizzy. They also can cause breathing problems, and you can become dependent on them, where you feel hooked and don't want to stop taking them.

Oral: Pertaining to the mouth.

Oral hygiene: Activities you do to keep your mouth clean. These include brushing your teeth, cheeks, tongue and dentures. They also can include using mouthwash or dental floss, or having a dentist or hygienist clean your teeth.

Oral lichen planus: This condition may appear as white patches; red, swollen tissues; or open sores in the mouth. Oral lichen planus may cause discomfort like burning or pain.

Orthodontic treatment: Orthodontic treatment is used to make teeth line up correctly. Also see malocclusion. Braces are a kind of orthodontic treatment.

Osteonecrosis of the jaws: Severe loss of the jaw bone. Sometimes referred to as ONJ.

Osteoporosis: A disease that causes bones to become thin and brittle.

Over-the-counter: Medicines available for sale that you can get without a prescription from a doctor. Also referred to as OTC.

Peri-implantitis : This is an infection that develops around an implant. It can cause bone loss.

Periodontal disease: More commonly known as gum disease, it is caused by plaque. When the plaque is not removed it can cause your gums to pull away from your teeth. Your gums may also become inflamed and bleed easily.

Periodontitis: A severe form of gum disease which can lead to tooth loss.

Plaque: A soft, sticky, thin layer of bacteria that forms on your teeth all the time.

Primary teeth: This is the first set of teeth that you get when you are a child. These are sometimes called baby teeth.

Prophylaxis: Removal of plaque, calculus and stains from the tooth structures. Usually called a prophy or teeth cleaning, this procedure is performed in dental offices.

Radiograph: A picture of the bones or teeth inside the body. It also is called an X-ray.

Recede: This describes when the gums pull away from the teeth. It also can be called recession.

Root canal treatment: A dental treatment for a tooth infection. During a root canal, the blood supply and nerves of the tooth are removed. After that, the tooth is usually filled with a material and sealed, or is specially shaped and covered with an artificial tooth (a crown).

Sealant: A thin plastic coating that can be put on the tops of molars and premolars (the big teeth in the back of your mouth). Sealants get hard and keep food from getting packed in the surfaces of these teeth. They help prevent cavities.

Sinuses: The spaces in the bones of your face, located in the forehead and on either side of the nose.

Sjögren Syndrome: An illness in which the immune system attacks the body's own cells by mistake. It mainly causes dry mouth and dry eyes, but can affect other areas of the body like the joints.

Staining: Discoloration of tooth surfaces. Can happen as the result of injury, genetics, smoking, certain medications, drinking of coffee or tea but is ultimately a part of aging.

Stomatitis: An irritation of any of the soft tissues of the mouth: lips, gums, cheeks, tongue, floor or roof of the mouth.